The invention relates to hand trucks, in particular hand trucks designed for heavy loads with front and rear wheels and in which raising and lowering of the load is assisted by a power source, such as hydraulicly actuated pistons and cylinders.
One of the problems with moving large loads about an area using conventional hand trucks is that it often takes a great deal of effort to move the load between its generally upright position on the support surface or ground and its loaded position on the rearwardly tilted hand truck. As an aid in doing so, power assisted hand trucks have been developed See, for example, U.S. Pat. No. 4,091,942 issued May 30, 1978, to the present inventor.
A problem with many of the prior art powerassisted hand trucks is that while moving the load from its upright position to its rearwardly tilting, loaded position, at which it is carried by the hand truck, the rear or back end of the hand truck has a tendency to pitch forward about its front wheels. This movement must therefore be restricted by the user, such as by pressing down on the back end of the hand truck with the user's foot. Doing so can be quite difficult at times, especially when the load is very heavy, has an eccentrically positioned center of gravity or is positionally unstable.